1. Field
The following description relates to technology for automating diagnoses of crop growth, and more particularly, to an apparatus and method for non-destructively diagnosing crop growth using terahertz waves.
2. Description of the Related Art
The word “terahertz” is a combination of the prefix “tera” meaning a value obtained by raising 10 to the power of 12, and a unit of frequency “hertz.” Terahertz waves denote electromagnetic waves having frequencies of 0.1 to 10 THz, that is, wavelengths of 30 μm to 3 mm, in the electromagnetic wave spectrum. Thus, a terahertz wave is an electric wave having the shortest wavelength and is also a light wave having the longest wavelength. Technology employing such terahertz waves has not yet been exploited because an appropriate signal source or a detection technique has not been developed. However, due to recent remarkable advancement in scientific technology, various techniques are being introduced, and terahertz waves are being recognized as an important tool in future scientific technology fields. Terahertz waves have both the transmissivity of electromagnetic waves and the directivity of light waves. Thus, it is possible to obtain a transmission image, such as an X-ray image, using terahertz waves, and also to analyze unique physical properties of a material from the terahertz region of a spectrum. For this reason, terahertz waves are also referred to as T-rays.
Since terahertz waves have superior transmissivity to existing X-ray imaging or magnetic resonance imaging (MRI), and can transmit a large amount of information several thousand times that of existing mobile communication, research is under way to apply terahertz wave technology to a variety of fields, such as histopathological diagnosis and molecular research. Since terahertz waves as a source for imaging have sufficiently short wavelengths compared to traditional microwaves, terahertz waves have excellent spatial resolution and can pass through most objects except water and metal. Also, due to a lower frequency than X-rays, it is possible to obtain a high-resolution image without damaging the skin tissue of a person.
Meanwhile, to harvest crops, for example, to automatically harvest oriental melons, it is necessary to select properly ripened oriental melons. When oriental melons are covered by leaves, it is necessary to find how ripe the oriental melons are by drawing the leaves aside and taking images of the oriental melons. Currently, the operation of drawing leaves is manually performed. When the operation is automated, it lacks reliability because it is necessary to draw a large number of leaves. Also, in comparison with a case in which a person manually performs the operation, crops suffer greater damage.